docs: actualizar .env.example con variables de Evolution, bot y webhook

Co-authored-by: aider (openrouter/openai/gpt-5) <aider@aider.chat>

.env.example

@@ -1,15 +1,23 @@
 # .env.example
+
+# Evolution API
 EVOLUTION_API_URL="https://example-url.com"
 EVOLUTION_API_KEY="example-api-key"
 EVOLUTION_API_INSTANCE="example-instance"
+
+# WhatsApp
 WHATSAPP_COMMUNITY_ID="example-community-id@g.us"
-CHATBOT_PHONE_NUMBER="1234567890"
-PORT="3007"
-WEBHOOK_URL="https://example-url.com/webhook"
+CHATBOT_PHONE_NUMBER="1234567890" # Número normalizado del bot; evita auto-respuestas
+
+# Webhook de este servicio
+WEBHOOK_URL="http://your-service-internal-url:3007" # URL interna a la que Evolution API enviará webhooks
+PORT=3007
+
+# Runtime
 NODE_ENV="production"
 
-# Group sync interval in milliseconds (default: 24h = 86400000ms)
-# - Set lower during development (e.g. 60000 = 1 minute)
-# - Minimum 10000ms (10s) enforced in development
-# - Format: plain number without quotes
+# Opcional: intervalo de sincronización de grupos en milisegundos (por defecto: 86400000 = 24h)
+# - Usar menor durante desarrollo (p.ej. 60000 = 1 minuto)
+# - Mínimo 10000ms (10s) forzado en development
+# - Formato: número sin comillas
 # GROUP_SYNC_INTERVAL_MS=86400000